超大型加氢筒体用钢SA-336F11CL3的冶炼方法研究

通过分析大型加氢反应器锻件用钢的特点,严格控制钢水中残余元素含量和X、J系数。确定采用"EBT→LF→VD→VC"的冶炼浇注工艺,成功浇注了4支SA-360F11CL3超大型加氢筒体锻件钢锭,其化学成分及各项指标均符合技术要求。     

大型空心钢锭锻造工艺探讨

大型压力容器筒体锻造过程中,使用空心钢锭相比于实心钢锭具有偏析少、材料利用率高、周期短等优点。通过物理模拟和数值模拟相结合的方法,研究了空心钢锭锻造工艺中压下率、拔长V型砧夹角等工艺参数对变形的影响规律和作用效果,以期为大型空心钢锭锻造工艺的制定提供实验依据和理论基础。     

大型钢锭模铸造工艺的研究与应用

通过对大型钢锭模的产品特征、材质特性、结构设计、铸造工艺等方面的研究与应用,归纳并提出保证钢锭模内壁质量的铸造工艺方案,对提高钢锭模使用寿命具有重要意义。     

大型筒体锻造工艺参数特性模拟研究

目前国内对制定加工效率高、成本低的空心钢锭锻造筒体工艺缺少科学依据。空心钢锭锻造过程中塑性变形规律较实心钢锭发生了很大变化,文章通过云纹实验和数值模拟相结合的方法对大型筒体锻造过程中单砧压下率、砧宽比、错砧角度、芯轴尺寸等工艺参数对变形规律的影响进行了研究,为提高大型筒体锻件质量提供了的实验依据和理论基础。     

高性能不锈钢无缝钢管的加工工艺

本发明涉及一种不锈钢无缝钢管的加工工艺,是一种用于超临界电站锅炉大容量机组、核电机组、石油裂化装置、大型煤液化装置等领域的高性能不锈钢无缝钢管的加工工艺。其生产工艺流程为：圆钢准备→圆钢加热→热轧穿孔→切头→酸洗→修磨→润滑→冷轧→脱脂→固溶热处理→矫直→切管→白化→包装入库。圆钢中加入了Cu、Nb、N、Mn和Ti,其中Cu2．5％-3．5％,Nb0．2％-0．6％,N0．05％-0．12％,Mn≤0．5％,Ti0．07％-0．13％。     

制造大直径厚壁管的工艺特点

研究了用各种原始毛坯生产大型厚壁管的工艺过程，分析了工艺参数对被获得制件的质量和金属制用系数的影响。确定了根据钢锭尺寸冷却冲孔钢锭的时间。     

大型筒体锻件空心钢锭锻造工艺探索

针对反应堆压力容器等大型筒体锻件采用实心钢锭存在的钢锭利用率低和生产周期长等缺点,对空心钢锭锻造工艺进行优化。通过铅试件物理模拟和DEFORM-3D数值模拟,研究空心钢锭在不同压下率、芯轴直径、砧宽、芯轴转角、接砧量和布砧方式下镦粗、芯轴拔长和芯轴扩孔时的变形规律,提出了避免空心锻造缺陷的方法,可为国产大型筒体锻件的空心钢锭锻造工艺规范制定提供参考依据。     

长轴类大锻件锻前加热工艺规范的优化

大型钢锭的加热为非线性过程,其心部温度无法直接探测,如何制定合理的大型钢锭加热工艺规范成为大型锻件锻造过程中首要解决的关键技术问题.采用Deform-3D软件对某船用螺旋桨轴锻造用钢锭锻前加热工艺规范进行了数值模拟,对加热过程中的温度场及应力场进行了分析,并对加热过程中安全性进行了评估.在此基础上,对加热工艺规范进行了...     

大型钢锭模铸造工艺的改进

针对以往大型钢锭模铸件内壁极易出现粘砂、夹砂、气孔、外表面板易有砂眼、缩孔及"胀肚"等缺陷,提出了大型钢锭模铸件铸造工艺的改进措施,使该铸件一级品达80%以上,废品率为零.     

液压机上自由锻及其质量控制

本文综述了大型锻件的生产特点及其影响因素、钢锭及钢坯加热要点、大型锻件锻造工艺规程及工艺装置、大锻件锻后冷却及热处理等重要内容。其中包括大型锻件锻造的质量控制。     

第三代AP1000核电主管道的研制

根据AP1000主管道热段的结构特点、技术难点和316LN超低碳奥氏体不锈钢的材料特性,中国二重在超大型不锈钢钢锭冶炼和浇注、大型不锈钢毛坯锻造、大直径小弯曲半径管道弯曲成型、不锈钢大直径旁通管嘴相贯线机加工和大直径不锈钢管道热处理等领域开展了重点攻关,在国际上率先研制成功AP1000主管道热段试制件,其技术指标达到国...     

锭模斜度及浇注工艺对钢锭质量影响的数值模拟研究

采用THERCAST模拟软件,模拟35 t钢锭的浇注和凝固过程,分析钢锭内部缺陷形成的原因。模拟计算锭模斜度、浇注温度和浇注速度对缺陷分布的影响,得出材料为30Cr Ni Mo8的35 t钢锭最佳浇注工艺方案。     

攀钢重轨钢钢水中氢含量的变化

攀钢在氧气顶吹转炉冶炼重轨钢过程中,熔池中钢水氢含量一直保持在很低的水平,并且在出钢、浇铸等工序中氢含量增加很少其中冶炼终点平均氢含量2.0(旱季)到2.4ppm(雨季),钢水包中2.8ppm,锭模中平均2.1(旱季)到2.3ppm(雨季),与钢水经真空RH处理的水平相当氧气顶吹转炉冶炼和攀枝花地区干旱的自然气候条件造成这种极低的氢含量是攀钢重轨钢无白点现象的主要原因     

A Numerical Study of the Effect of Multiple Pouring on Macrosegregation in a 438-Ton Steel Ingot

In present paper, a ladle–tundish–mold CFD model and a macrosegregation model were utilized to investigate the effects of the multiple pouring(MP) process on the macrosegregation in a 438-ton steel ingot. Firstly, the model was partially proved as compared to the measured carbon distributions along the transverse sections in the riser of ingot. Then, the comparison between the single pouring(SP) and MP process has been carried out to study their influences on the macrosegregation in ingot. Besides, the predicted macrosegregation results in MP process which introduced the improved riser fixed with an insulating sleeve were compared with that in traditional MP process. The traditional MP process leads to certain favorable initial carbon distribution in the mold, which has some favorable influence on suppressing the positive segregation in ingot. The holding time of the low carbon in the riser is the main factor to suppress the positive segregation in ingot. Improved insulating sleeve can prolong the holding time of the low carbon in the riser and release the positive segregation in the riser of ingot. Improvement of the insulating effect of the riser is an efficient method to control macrosegregation in large steel ingot.     

精炼包真空直注工艺开发

介绍精炼包真空直注设备改造、工艺开发及工业实践.该工艺可以避免中间包真空浇注过程中的钢水二次氧化、中间包耐材侵蚀、中间包塞棒关不死引起下渣等问题,减少进入钢锭内部的夹杂物数量,提高钢锭质量.     

Numerical Simulation of Macrosegregation in Steel Ingot CastingEI北大核心CSCD

Many key forging components of heavy equipment are manufactured by large steel ingots. Macrosegregation in steel ingots is a key defect formed during the solidification process. Over the past few decades, numerical modeling has played a more and more important role in the study of macrosegregation. Various models have been developed and applied to different ingot casting processes. This paper focused on the application of macrosegregation models to the steel ingot. Firstly, the formation mechanism and influencing factors of macrosegregation were introduced. Then, the existing macrosegregation models and their recent development were summarized. Macrosegregation models accounting for such mechanisms as solidification shrinkage- induced flow and mushy zone deformation were analyzed, respectfully. To model macrosegregation due to solidification shrinkage, the key was to solve the free surface. A simple derivation showed that the multi-phase (including gas phase) models were equivalent to the VOF-based segregation models in dealing with the shrinkage-induced flow. Finally, our recent research work on numerical modeling of macrosegregation in steel ingots was illustrated, including application of the developed multi-component and multi-phase macrosegregation model to a 36 t steel ingot, and numerical simulation of multiple pouring process. The carbon and sulphur concentrations at about 1800 sampling points, covering the full section of a 36 t ingot, were measured. By detailed temperature recording, accurate heat transfer conditions between the ingot and mould were obtained. Typical macrosegregation patterns, including the bottom-located negative segregation and the pushpin-like positive segregation zone in the top riser, have been reproduced both in the measurements and the predictions, The carbon and sulphur concentrations predicted by the three dimensional multi-component and multi-phase macrosegregation models agreed well with the measurements, thus proving that the model can well predict the macrosegregation formation in steel ingots. As for the multi-pouring process simulation, the results show a high concentration of carbon at the bottom and a low concentration of carbon at the top of the mould after the multi-pouring process with carbon content high in the first ladle and low in the last ladle. Therefore, the multiple pouring process could get the initial solute distribution with the opposite form of segregation. Such carbon concentration distribution would reduce the negative segregation at the bottom and the positive segregation at the top of the solidified ingot, thus proving the ability of the multiple pouring process for the control of macrosegregation.     

Formation mechanism of shrinkage and large inclusions of a 70t 12Cr2Mo1 heavy steel ingot简

Shrinkage cavities and large inclusions are serious internal defects of heavy steel ingot and influence the quality of subsequent forgings.In order to remove these two types of defects,a 70 t 12Cr2Mo1 heavy ingot fabricated by vacuum carbon de-oxidation process was sectioned and investigated by means of structure observation and EDS analysis.To further study the forming mechanism of shrinkage and inclusion defects and find possible solutions,simulation on pouring and solidification processes was also carried out using Fluent and ProCAST software,respectively.Results show that the shrinkage defects do not appear in the middle-upper part of the ingot.The critical value of shrinkage cavity criterion is ascertained as 0.013 on the basis of sectioning investigation and simulation results,which can be used in computer simulation to predict and avoid shrinkage defects in production of 12Cr2Mo1 ingots with different weights.However,large inclusions are found at the bottom of the ingot body.The bad thermal conditions of the ingot surface and large amount of entrained slag are the main origin of the large inclusions.The simulation result of the pouring process shows that large inclusions may be eliminated by combined measures of improving the top thermal condition and controlling the height of rudimental molten steel in the ladle to above 300 mm.     

提高冷轧不锈钢管成材率的新工艺

采用φ95mm不锈管坯,经扒皮→φ100mm机组穿孔+轧管→LG-80冷轧管机轧管的新工艺生产φ57×3～4mm不锈钢管,产品质量和成材率明显提高。     

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 对用40CrNiMo钢制成的万吨海洋作业平台爬升齿轮轴心开裂的样品进行了观察分析。通过化学成分分析、宏观检验、金相检验、SEM等方法对原因进行了分析。结果表明：原材料钢锭在浇注过程中控制不当是引起万吨海洋作业平台爬升齿轮轴心开裂的主要原因。通过对冶炼浇注工艺的调整和严格控制,使40CrNiMo钢制成的万吨海洋作业平台爬升齿轮超声波探伤均符合了标准要求。